Gout is a crystal arthropathy due to deposition of monosodium urate crystals in and around the joints. There is a strong male predilection (20:1).

Four stages of gout are seen - asymptomatic hyperuricemia, acute gouty arthritis, intercritical gout (between acute attacks) and chronic tophaceous gout.

Characteristic radiologic changes occur in the chronic stage, though not all patients progress to this. There is a predilection for the small joints of the hands and feet. The typical appearance is well-defined “punched-out” erosions with sclerotic margins in a marginal and juxta-articular distribution, with overhanging edges. The joint space is preserved until late. Chondrocalcinosis is present in 5%. Periarticular soft tissue swelling due to crystal deposition in tophi around the joints is common. This soft tissue swelling may be hyperdense due to the crystals, and the tophi frequently calcify.

Credit: Dr Donna D'Souza.